Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 406 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/Structure.h b/Source/JavaScriptCore/runtime/Structure.h
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+/*
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef Structure_h
+#define Structure_h
+
+#include "ClassInfo.h"
+#include "Identifier.h"
+#include "JSCell.h"
+#include "JSType.h"
+#include "JSValue.h"
+#include "PropertyMapHashTable.h"
+#include "PropertyNameArray.h"
+#include "Protect.h"
+#include "StructureTransitionTable.h"
+#include "JSTypeInfo.h"
+#include "UString.h"
+#include "Weak.h"
+#include <wtf/PassOwnPtr.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/RefCounted.h>
+
+
+namespace JSC {
+
+    class PropertyNameArray;
+    class PropertyNameArrayData;
+    class StructureChain;
+    class SlotVisitor;
+
+    class Structure : public JSCell {
+    public:
+        friend class StructureTransitionTable;
+
+        typedef JSCell Base;
+
+        static Structure* create(JSGlobalData& globalData, JSGlobalObject* globalObject, JSValue prototype, const TypeInfo& typeInfo, const ClassInfo* classInfo)
+        {
+            ASSERT(globalData.structureStructure);
+            ASSERT(classInfo);
+            Structure* structure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData, globalObject, prototype, typeInfo, classInfo);
+            structure->finishCreation(globalData);
+            return structure;
+        }
+
+    protected:
+        void finishCreation(JSGlobalData& globalData)
+        {
+            Base::finishCreation(globalData);
+            ASSERT(m_prototype);
+            ASSERT(m_prototype.isObject() || m_prototype.isNull());
+        }
+
+        void finishCreation(JSGlobalData& globalData, CreatingEarlyCellTag)
+        {
+            Base::finishCreation(globalData, this, CreatingEarlyCell);
+            ASSERT(m_prototype);
+            ASSERT(m_prototype.isNull());
+            ASSERT(!globalData.structureStructure);
+        }
+
+    public:
+        static void dumpStatistics();
+
+        static Structure* addPropertyTransition(JSGlobalData&, Structure*, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset);
+        static Structure* addPropertyTransitionToExistingStructure(Structure*, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset);
+        static Structure* removePropertyTransition(JSGlobalData&, Structure*, const Identifier& propertyName, size_t& offset);
+        static Structure* changePrototypeTransition(JSGlobalData&, Structure*, JSValue prototype);
+        static Structure* despecifyFunctionTransition(JSGlobalData&, Structure*, const Identifier&);
+        static Structure* getterSetterTransition(JSGlobalData&, Structure*);
+        static Structure* toCacheableDictionaryTransition(JSGlobalData&, Structure*);
+        static Structure* toUncacheableDictionaryTransition(JSGlobalData&, Structure*);
+        static Structure* sealTransition(JSGlobalData&, Structure*);
+        static Structure* freezeTransition(JSGlobalData&, Structure*);
+        static Structure* preventExtensionsTransition(JSGlobalData&, Structure*);
+
+        bool isSealed(JSGlobalData&);
+        bool isFrozen(JSGlobalData&);
+        bool isExtensible() const { return !m_preventExtensions; }
+        bool didTransition() const { return m_didTransition; }
+
+        Structure* flattenDictionaryStructure(JSGlobalData&, JSObject*);
+
+        static void destroy(JSCell*);
+
+        // These should be used with caution.  
+        size_t addPropertyWithoutTransition(JSGlobalData&, const Identifier& propertyName, unsigned attributes, JSCell* specificValue);
+        size_t removePropertyWithoutTransition(JSGlobalData&, const Identifier& propertyName);
+        void setPrototypeWithoutTransition(JSGlobalData& globalData, JSValue prototype) { m_prototype.set(globalData, this, prototype); }
+        
+        bool isDictionary() const { return m_dictionaryKind != NoneDictionaryKind; }
+        bool isUncacheableDictionary() const { return m_dictionaryKind == UncachedDictionaryKind; }
+
+        // Type accessors.
+        const TypeInfo& typeInfo() const { ASSERT(structure()->classInfo() == &s_info); return m_typeInfo; }
+        bool isObject() const { return typeInfo().isObject(); }
+
+
+        JSGlobalObject* globalObject() const { return m_globalObject.get(); }
+        void setGlobalObject(JSGlobalData& globalData, JSGlobalObject* globalObject) { m_globalObject.set(globalData, this, globalObject); }
+        
+        JSValue storedPrototype() const { return m_prototype.get(); }
+        JSValue prototypeForLookup(ExecState*) const;
+        StructureChain* prototypeChain(ExecState*) const;
+        static void visitChildren(JSCell*, SlotVisitor&);
+
+        Structure* previousID() const { ASSERT(structure()->classInfo() == &s_info); return m_previous.get(); }
+        bool transitivelyTransitionedFrom(Structure* structureToFind);
+
+        void growPropertyStorageCapacity();
+        unsigned propertyStorageCapacity() const { ASSERT(structure()->classInfo() == &s_info); return m_propertyStorageCapacity; }
+        unsigned propertyStorageSize() const { ASSERT(structure()->classInfo() == &s_info); return (m_propertyTable ? m_propertyTable->propertyStorageSize() : static_cast<unsigned>(m_offset + 1)); }
+        bool isUsingInlineStorage() const;
+
+        size_t get(JSGlobalData&, const Identifier& propertyName);
+        size_t get(JSGlobalData&, const UString& name);
+        size_t get(JSGlobalData&, StringImpl* propertyName, unsigned& attributes, JSCell*& specificValue);
+        size_t get(JSGlobalData& globalData, const Identifier& propertyName, unsigned& attributes, JSCell*& specificValue)
+        {
+            ASSERT(!propertyName.isNull());
+            ASSERT(structure()->classInfo() == &s_info);
+            return get(globalData, propertyName.impl(), attributes, specificValue);
+        }
+
+        bool hasGetterSetterProperties() const { return m_hasGetterSetterProperties; }
+        void setHasGetterSetterProperties(bool hasGetterSetterProperties) { m_hasGetterSetterProperties = hasGetterSetterProperties; }
+
+        bool hasNonEnumerableProperties() const { return m_hasNonEnumerableProperties; }
+        
+        bool isEmpty() const { return m_propertyTable ? m_propertyTable->isEmpty() : m_offset == noOffset; }
+
+        void despecifyDictionaryFunction(JSGlobalData&, const Identifier& propertyName);
+        void disableSpecificFunctionTracking() { m_specificFunctionThrashCount = maxSpecificFunctionThrashCount; }
+
+        void setEnumerationCache(JSGlobalData&, JSPropertyNameIterator* enumerationCache); // Defined in JSPropertyNameIterator.h.
+        JSPropertyNameIterator* enumerationCache(); // Defined in JSPropertyNameIterator.h.
+        void getPropertyNamesFromStructure(JSGlobalData&, PropertyNameArray&, EnumerationMode);
+
+        bool staticFunctionsReified()
+        {
+            return m_staticFunctionReified;
+        }
+
+        void setStaticFunctionsReified()
+        {
+            m_staticFunctionReified = true;
+        }
+
+        const ClassInfo* classInfo() const { return m_classInfo; }
+
+        static ptrdiff_t prototypeOffset()
+        {
+            return OBJECT_OFFSETOF(Structure, m_prototype);
+        }
+
+        static ptrdiff_t typeInfoFlagsOffset()
+        {
+            return OBJECT_OFFSETOF(Structure, m_typeInfo) + TypeInfo::flagsOffset();
+        }
+
+        static ptrdiff_t typeInfoTypeOffset()
+        {
+            return OBJECT_OFFSETOF(Structure, m_typeInfo) + TypeInfo::typeOffset();
+        }
+
+        static Structure* createStructure(JSGlobalData& globalData)
+        {
+            ASSERT(!globalData.structureStructure);
+            Structure* structure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData);
+            structure->finishCreation(globalData, CreatingEarlyCell);
+            return structure;
+        }
+        
+        static JS_EXPORTDATA const ClassInfo s_info;
+
+    private:
+        Structure(JSGlobalData&, JSGlobalObject*, JSValue prototype, const TypeInfo&, const ClassInfo*);
+        Structure(JSGlobalData&);
+        Structure(JSGlobalData&, const Structure*);
+
+        static Structure* create(JSGlobalData& globalData, const Structure* structure)
+        {
+            ASSERT(globalData.structureStructure);
+            Structure* newStructure = new (NotNull, allocateCell<Structure>(globalData.heap)) Structure(globalData, structure);
+            newStructure->finishCreation(globalData);
+            return newStructure;
+        }
+        
+        typedef enum { 
+            NoneDictionaryKind = 0,
+            CachedDictionaryKind = 1,
+            UncachedDictionaryKind = 2
+        } DictionaryKind;
+        static Structure* toDictionaryTransition(JSGlobalData&, Structure*, DictionaryKind);
+
+        size_t putSpecificValue(JSGlobalData&, const Identifier& propertyName, unsigned attributes, JSCell* specificValue);
+        size_t remove(const Identifier& propertyName);
+
+        void createPropertyMap(unsigned keyCount = 0);
+        void checkConsistency();
+
+        bool despecifyFunction(JSGlobalData&, const Identifier&);
+        void despecifyAllFunctions(JSGlobalData&);
+
+        PassOwnPtr<PropertyTable> copyPropertyTable(JSGlobalData&, Structure* owner);
+        PassOwnPtr<PropertyTable> copyPropertyTableForPinning(JSGlobalData&, Structure* owner);
+        void materializePropertyMap(JSGlobalData&);
+        void materializePropertyMapIfNecessary(JSGlobalData& globalData)
+        {
+            ASSERT(structure()->classInfo() == &s_info);
+            if (!m_propertyTable && m_previous)
+                materializePropertyMap(globalData);
+        }
+        void materializePropertyMapIfNecessaryForPinning(JSGlobalData& globalData)
+        {
+            ASSERT(structure()->classInfo() == &s_info);
+            if (!m_propertyTable)
+                materializePropertyMap(globalData);
+        }
+
+        int transitionCount() const
+        {
+            // Since the number of transitions is always the same as m_offset, we keep the size of Structure down by not storing both.
+            return m_offset == noOffset ? 0 : m_offset + 1;
+        }
+
+        bool isValid(ExecState*, StructureChain* cachedPrototypeChain) const;
+        
+        void pin();
+
+        static const int s_maxTransitionLength = 64;
+
+        static const int noOffset = -1;
+
+        static const unsigned maxSpecificFunctionThrashCount = 3;
+
+        TypeInfo m_typeInfo;
+        
+        WriteBarrier<JSGlobalObject> m_globalObject;
+        WriteBarrier<Unknown> m_prototype;
+        mutable WriteBarrier<StructureChain> m_cachedPrototypeChain;
+
+        WriteBarrier<Structure> m_previous;
+        RefPtr<StringImpl> m_nameInPrevious;
+        WriteBarrier<JSCell> m_specificValueInPrevious;
+
+        const ClassInfo* m_classInfo;
+
+        StructureTransitionTable m_transitionTable;
+
+        WriteBarrier<JSPropertyNameIterator> m_enumerationCache;
+
+        OwnPtr<PropertyTable> m_propertyTable;
+
+        uint32_t m_propertyStorageCapacity;
+
+        // m_offset does not account for anonymous slots
+        int m_offset;
+
+        unsigned m_dictionaryKind : 2;
+        bool m_isPinnedPropertyTable : 1;
+        bool m_hasGetterSetterProperties : 1;
+        bool m_hasNonEnumerableProperties : 1;
+        unsigned m_attributesInPrevious : 7;
+        unsigned m_specificFunctionThrashCount : 2;
+        unsigned m_preventExtensions : 1;
+        unsigned m_didTransition : 1;
+        unsigned m_staticFunctionReified;
+    };
+
+    inline size_t Structure::get(JSGlobalData& globalData, const Identifier& propertyName)
+    {
+        ASSERT(structure()->classInfo() == &s_info);
+        materializePropertyMapIfNecessary(globalData);
+        if (!m_propertyTable)
+            return notFound;
+
+        PropertyMapEntry* entry = m_propertyTable->find(propertyName.impl()).first;
+        return entry ? entry->offset : notFound;
+    }
+
+    inline size_t Structure::get(JSGlobalData& globalData, const UString& name)
+    {
+        ASSERT(structure()->classInfo() == &s_info);
+        materializePropertyMapIfNecessary(globalData);
+        if (!m_propertyTable)
+            return notFound;
+
+        PropertyMapEntry* entry = m_propertyTable->findWithString(name.impl()).first;
+        return entry ? entry->offset : notFound;
+    }
+    
+    inline bool JSCell::isObject() const
+    {
+        return m_structure->isObject();
+    }
+
+    inline bool JSCell::isString() const
+    {
+        return m_structure->typeInfo().type() == StringType;
+    }
+
+    inline bool JSCell::isGetterSetter() const
+    {
+        return m_structure->typeInfo().type() == GetterSetterType;
+    }
+
+    inline bool JSCell::isAPIValueWrapper() const
+    {
+        return m_structure->typeInfo().type() == APIValueWrapperType;
+    }
+
+    inline void JSCell::setStructure(JSGlobalData& globalData, Structure* structure)
+    {
+        ASSERT(structure->typeInfo().overridesVisitChildren() == this->structure()->typeInfo().overridesVisitChildren());
+        ASSERT(structure->classInfo() == m_structure->classInfo());
+        m_structure.set(globalData, this, structure);
+    }
+
+    inline const ClassInfo* JSCell::validatedClassInfo() const
+    {
+#if ENABLE(GC_VALIDATION)
+        ASSERT(m_structure.unvalidatedGet()->classInfo() == m_classInfo);
+#else
+        ASSERT(m_structure->classInfo() == m_classInfo);
+#endif
+        return m_classInfo;
+    }
+
+    ALWAYS_INLINE void MarkStack::internalAppend(JSCell* cell)
+    {
+        ASSERT(!m_isCheckingForDefaultMarkViolation);
+#if ENABLE(GC_VALIDATION)
+        validate(cell);
+#endif
+        m_visitCount++;
+        if (Heap::testAndSetMarked(cell) || !cell->structure())
+            return;
+        
+        // Should never attempt to mark something that is zapped.
+        ASSERT(!cell->isZapped());
+        
+        m_stack.append(cell);
+    }
+
+    inline StructureTransitionTable::Hash::Key StructureTransitionTable::keyForWeakGCMapFinalizer(void*, Structure* structure)
+    {
+        // Newer versions of the STL have an std::make_pair function that takes rvalue references.
+        // When either of the parameters are bitfields, the C++ compiler will try to bind them as lvalues, which is invalid. To work around this, use unary "+" to make the parameter an rvalue.
+        // See https://bugs.webkit.org/show_bug.cgi?id=59261 for more details.
+        return Hash::Key(structure->m_nameInPrevious.get(), +structure->m_attributesInPrevious);
+    }
+
+    inline bool Structure::transitivelyTransitionedFrom(Structure* structureToFind)
+    {
+        for (Structure* current = this; current; current = current->previousID()) {
+            if (current == structureToFind)
+                return true;
+        }
+        return false;
+    }
+
+    inline JSCell::JSCell(JSGlobalData& globalData, Structure* structure)
+        : m_classInfo(structure->classInfo())
+        , m_structure(globalData, this, structure)
+    {
+    }
+
+    inline void JSCell::finishCreation(JSGlobalData& globalData, Structure* structure, CreatingEarlyCellTag)
+    {
+#if ENABLE(GC_VALIDATION)
+        ASSERT(globalData.isInitializingObject());
+        globalData.setInitializingObject(false);
+        if (structure)
+#endif
+            m_structure.setEarlyValue(globalData, this, structure);
+        m_classInfo = structure->classInfo();
+        // Very first set of allocations won't have a real structure.
+        ASSERT(m_structure || !globalData.structureStructure);
+    }
+
+} // namespace JSC
+
+#endif // Structure_h